you can do nothing to ensure success ; there are no logical rules of discovery . but you can prepare yourself , and you must , so that when the unexpected finding , or odd phenomenon , or technological breakthrough occurs , it can be you who is best equipped to grasp its significance . preparing means mastering bodies of knowledge and techniques known to be relevant , but also  and here i borrow not from advice but from cajal s remarkable biography  recognizing that sometimes knowledge and skills acquired from the necessity of circumstance will prove critical . so it was for cajal , who , initially indifferent to medicine and needing a trade , was apprenticed to a barber . this granted such dexterity with a razor that when he finally came to the study of anatomy , his histological preparations were unusually skillful , enabling him able to see neural structures with exceptional clarity . this theme is really a corollary of the first , but leads to a different moral . undue focus on this quality can engender worship of yesterday s abilities and insights , and this can hold individuals  indeed , entire fields  back . never let perceived lack of ability limit you especially when it s a self - perception . lack of ability  may simply be a set of skills waiting for its moment . besides , as cajal writes ,  work substitutes for talent , or better  it creates talent .  the scientist s single most important virtue is perseverance . no theory , no method , and no experimental paradigm is perfect . do not defend or dismiss the errors of your teachers ; use them to identify new problems to solve . finding the time and space for extended and total concentration on a problem is vital . on these occasions shut out everything inessential : email , facebook , politics . all scientific findings are useful , eventually . the call to specify in advance the use of an investigation represents a lack of faith in the scientific enterprise , and of necessity limits creativity . cajal lists a dozen phenomena that , had we waited to know what they might be good for before investigating further , would never have been good for anything at all , and we would now lack such tools as batteries , photography , and x - rays . when access to money , tools , or space would come at the cost of your autonomy , choose autonomy . successful science can be pursued on any scale , but freedom of thought is non - negotiable . this may seem nave in the age of big science , but it reflects my own experience . my most important work was begun as an unfunded side - project , and came to fruition in the lightly - subsidized lab of a small liberal arts college . my investigations were tailored to what undergraduate assistants could manage and , when i could nt afford to generate my own data , i borrowed the data of others . you may object that such advice is hardly the basis for a universal principle : those data took money to produce , just not my own . , some will be successful enough to direct the large , well - funded projects that will produce the data , and miss the problems that will allow the next young investigators to move decisively beyond them . so will be the next . for there are no small problems in science , only phenomena so incompletely understood as to seem so . in science , notes cajal ( quoting geoffroy saint - hilaire ) ,  the infinite is always before us . there is much more to this book than this sampling captures , including advice to the teacher , and even for choosing a life partner . that cajal would think to include this latter is endearing , and , although his discussion is choked with objectionable stereotypes , the attempt reflects the positive and affirming thought that science is part of life , and should ideally be made seamless with it . this pull - yourself - up - by - your - bootstraps attitude will not please everyone  this is decidedly not a work of activism . ( no bootstraps ? guess you ll need to make some first . how about twine ? ) but it is what gives the book its utility to the young investigator needing to make his or her way in their particular time , place , and situation . cajal was acutely aware not just of spain s physical , but also cultural distance from the great scientific centers of the world , and his call for spain to acknowledge and repay its accruing  debt to civilization  has a kennedy - esque ring . his book is intended in part , i think , as a reminder that those in a position to contribute to the advance of scientific knowledge , in whatever way and to whatever degree their situations and abilities allow , have a sacred obligation to do so . and cajal does mean sacred . it may be that the spiritual attitude that suffuses the book embodies the most important advice in advice . science is not just a collection of techniques or strategies for producing knowledge , it is an ethical stance of commitment to the truth . the good scientist knows that honestly following the evidence is a form of respect for nature , and honestly communicating one s findings is a form of respect for others . recognizing the fallibility of both experiment and reason brings humility , and also charity . knowing that ultimately science only progresses in collaboration builds community . acknowledging the ways that science and scientists serially fail to embody these virtues does nothing to lessen their importance or authority .
editor s note : santiago ramn y cajal , a mythic figure in science and recognized as the father of modern anatomy and neurobiology , was largely responsible for the modern conception of the brain . 
 the first to publish on the nervous system , he sought to educate the novice scientist about how he thought science should be done . 
 we asked an accomplished young investigator to take a fresh look at this recently rediscovered classic , first published in 1897 .